1. Field of The Invention
The present invention relates generally to a ribbon cartridge. Particularly, the present invention relates to a ribbon cartridge which may be employed in a color printer, for example.
2. Description of The Prior Art
A ribbon cartridge is well known in which a ribbon is permeated with colors, such as yellow, magenta and cyan for continuous color printing. Such a conventional ribbon cartridge includes a ribbon supply reel and a ribbon take-up reel winding a ribbon therebetween. Referring to FIGS. 13 and 14, such a conventional ribbon cartridge will be described hereinbelow in detail.
A ribbon cartridge 100 includes a cartridge body 101 comprised of a lower casing 102 and an upper casing 103, joined by ultrasonic welding or the like. The lower casing 102 comprises at the sides thereof, straight portions 102a and 102b, situated between curved end portions 102c and 102d. The straight and curved portions are formed integrally of synthetic resin or the like. The upper casing 103 likewise has corresponding straight side members 103a and 103b as well as semicircular end members 103c and 103d corresponding to the curved portions 102c and 102d of the lower casing 102. One each side of a central area of the upper casing 103, edge portions 102e, 103e are provided for defining an opening 106 for exposing a ribbon.
Between the end portions 102c, 103c and 102d and 103d of the lower and upper casings a ribbons supply reel 110 and a ribbon take-up reel 111 are provided respectively. Wound between the supply reel 110 and take-up reel 111 is an ink ribbon 120 permeated with yellow (Y), magenta (M) and cyan (C) inks, or dyes for example. Further, substantially centered within the circle formed by end portions 102c, 103c, and 102d, 103d, on the same side of the cartridge as the side members 103a and 102a rotational axis portions 104, 104 are mounted. Also, substantially centered within the circle formed by end portions 102c, 103c, and 102d, 103d, on the same side of the cartridge as the side members 103b and 102b rotational axis portions 105, 105 are mounted. The axis portions 104, 105 are axially aligned across the circular reel housings formed by the casing portions 102c, 103c and 102d and 103d respectively. One axis portion 104 and one axis portion 105 is required for rotatably mounting one of the reels 110 or 111 therebetween.
In the above described conventional ribbon cartridge 100, since the cartridge encloses both supply and take-up reels 110 and 111 housed in end portions 102c, 103c and 102d and 103d of the casings 102 and 103, the size of the cartridge become large and increases a manufacturing cost thereof. Further, the large size and double reel configuration make correct installation and removal more difficult. Further, openings 106, 106 defined between edge portions 102e and 103e on both supply and take-up sides of the cartridge body 101 must be substantially large and may easily admit dust etc., which may degrade image quality and/or printer performance. Also, the take up reel preserves the images printed by the printer on the spent ink ribbon 120 which may compromise the security of documents printed on the printer in which such a cartridge is employed.